New York has always had big dogs, traders who felt they knew better than the common herd and were anxious to let the world know it. They attack or defend big companies like they're cards in a poker game, and make the media part of the play. They're the lion tamers in the market circus, the bullfighters in the market bull ring. They're the market's high-wire acts.

Today's vehicle of choice is the hedge fund. Privately held, it's not subject to the rules that governed brokerages or conglomerates back in the day. Most hedge funds are quiet, taking the pennies that fall out of any quick market move, counting nickels and dimes a million times. Others are more active.

Ackman's Pershing Square Capital Management is an example of a more active fund. It makes big public bets, for and against big companies. When it's right, as with McDonald's or General Growth Properties it wins big. When it's wrong, as with Borders or Target, it loses big.

Trouble is, of course, that the know-it-all, I'm better-than-you attitude makes enemies. Wall Street nature is red in tooth and claw, so weakness in a big dog is seen by the rest of the pack as a cue to attack.

And that's what is happening to Ackman today. His bad bet on J.C. Penney, which included the hiring of former CEO Ron Johnson, has weakened him. But while that bet was failing, he bet bigger with a short of Herbalife, announcing it in December through a three-hour presentation whose highlights were then posted to a Web site.

Ackman claims to be shocked that other big dogs, like Dan Loeb of Third Point LLC, another hedge fund, and investor Carl Icahn, are taking the other side of the trade, aiming to squeeze him dry.